In the prior art, a tank toilet is usually manual, such as a knob-lifting type tank toilet and a button-piston type tank toilet, for example. A knob-lifting type tank toilet generally includes a rod, a lifting member and a knob. As it is needed to flush, the water in the tank can be released by rotating a knob, thereby moving a rod and lifting a lifting member to pull an outlet plug out so that a flush is completed. A piston-button type tank toilet generally includes a moveable outlet plug and a button structure. As it is needed to flush, a moveable outlet plug is lifted by pressing a button structure to flush.
With the development of technology, the old manual tank toilet can not satisfy people's needs. So, the automatic flush toilet appeared in the prior art. It senses the user by a sensor to control the flush and the automatic flush device controls the water flush by an electric motor to lift the outlet plug instead of handling by hands. This automatic flush toilet is more convenient and sanitary. Its operation principle is as follows. The sensor detects the user entering into a sensing area, and then it detects the user leaving the sensing area after a while. At this time, the sensor sends signals to an electronic sensor controller and then the controller judges that it is required to flush at this time according to a preset program. Thus, the controller drives the electric motor to pull the outlet plug out to release the water in the tank and flush the toilet.
In the prior art, a sensor not only detects the users, but also other things, such as the toilet lid. Generally speaking, when the toilet is used, the toilet lid is opened. Therefore the detection of the toilet lid position is also one of the preferred sensing methods. The sensing methods can be infrared sensing or electromagnet sensing, for example. In the prior art, there also exists microwave sensing and pressure sensing, for example.
However, the automatic flush toilet in the prior art needs extra power to drive the electric motor to rotate and bring out the outlet plug, requiring large power consumption. It is difficult to improve the old manual tank toilet to achieve the object of automatic flush.
Therefore, it is desirable to invent a reliable and energy-saving automatic flush device to be applied to a tank toilet. At the same time, it is desirable that this automatic flush device be easily usable with existing tank toilets, thereby upgrading existing manual tank toilets to achieve an automatic flush.